The role of corticosterone on retrieval of aversively motivated tasks in sleep deprived animals

• Grant number: 10/05372-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2010
• End date: December 31, 2011
• Field of knowledge: Biological Sciences - Pharmacology - Neuropsychopharmacology
• Principal Investigator: Deborah Suchecki
• Grantee: Mariella Bodemeier Loayza Careaga
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil
• Associated research grant: 98/14303-3 - Center for Sleep Studies, AP.CEPID

Abstract

Numerous studies have shown that sleep deprivation (SD) impact negatively on cognitive process, including learning and memory. Glucocorticoids (GC) are modulators of cognitive processes and these effects depend on both GC levels, as well as the phase of memory achieved: acquisition, consolidation and retrieval. The purpose of the present study is to evaluate whether memory deficits observed in sleep deprived animals before testing (i.e., when animals are under sleep deprivation during memory retrieval) are due to release of glucocorticoids, once they are elevated after sleep deprivation. Two tasks will be used, contextual (CFC) and tone fear conditioning (TFC). Animals will be trained and the consolidation period will be guaranteed by a 96h interval. After this time, the animals will be either sleep deprived or not (control group) for a period of time to be determined on the first experiment. Immediately after sleep deprivation, animals will be distributed into one of two groups: treated with metyrapone (MET - a corticosterone synthesis inhibitor) or vehicle, and then tested or sacrificed for plasma corticosterone/ACTH levels determination. If memory retrieval impairment in sleep deprived animals is due to elevated GC levels, inhibiting its synthesis might reverse this deleterious effect. (AU)